Honor REQUIRE_PARTS for ambiguous month-number inputs by retrying year-biased DATE_ORDER

[MrinalJain17]

Attempt to fix #1235.

Problem

When parsing inputs like Oct-23 with settings={"REQUIRE_PARTS": ["month", "year"]}, dateparser.parse can return None even though a valid interpretation exists (October 2023). The failure occurs because the initial DATE_ORDER (often locale-derived or the default) may interpret the trailing number as a day rather than a year, causing REQUIRE_PARTS validation to reject the result.

Fix

When all of the following are true:

• REQUIRE_PARTS includes "year" and does not require "day",
• the caller did not explicitly set DATE_ORDER,

We retry parsing the same translated string with year-biased DATE_ORDER candidates (MYD, then YMD) after the initial attempt. This allows ambiguous Mon-23 style inputs to resolve to month–year when that is the only way to satisfy the requested parts.

Scope / compatibility

• No behavior change for callers that do not use REQUIRE_PARTS.
• No behavior change when DATE_ORDER is explicitly set by the caller.
• No behavior change when REQUIRE_PARTS requires day (month–day remains valid).

[Copilot]

Pull request overview

This PR fixes an issue where dateparser.parse returns None for ambiguous month-number inputs like "Oct-23" when REQUIRE_PARTS specifies ["month", "year"]. The fix introduces a retry mechanism with year-biased DATE_ORDER candidates when the initial parse fails to satisfy the required parts constraint.

Key changes:

• Adds retry logic with year-biased DATE_ORDER values (MYD, YMD) when REQUIRE_PARTS includes "year" but not "day" and DATE_ORDER was not explicitly set
• Restructures _try_parser method to iterate through multiple DATE_ORDER candidates and handle parse failures gracefully
• Adds comprehensive test coverage for the new behavior, including edge cases for explicit DATE_ORDER and month-day requirements

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
tests/test_clean_api.py	Adds three test cases covering month-year parsing with REQUIRE_PARTS, explicit DATE_ORDER preservation, and month-day requirement scenarios
dateparser/date.py	Refactors _try_parser to support multiple DATE_ORDER candidates with proper retry logic and state restoration

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.61%. Comparing base (920d725) to head (3fa3bf1).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1298      +/-   ##
==========================================
+ Coverage   96.60%   96.61%   +0.01%     
==========================================
  Files         235      235              
  Lines        2889     2899      +10     
==========================================
+ Hits         2791     2801      +10     
  Misses         98       98              

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